In America, we love a success story. But we distrust too much success. No one today is more successful than Google. So it is no surprise that the US justice department appears to be looking at whether Google has grown too big and successful. The department last week hired Sanford Litvack, a well-known litigator and former head of antitrust under Jimmy Carter, to look into Google's deal to sell ads on Yahoo's pages - and, by implication, Google's dominion over the ad industry.

Google is dominant. It controls 87% of searches in the UK and 71% in the US, according to Hitwise. With its acquisition of Doubleclick, it serves 69% of internet ads, according to Attributor, and reaps 24% of online ad revenue, says IDC. Google's ad revenue grew past ITV's in 2008 and is expected to surpass that British national newspapers combined. Dominant is the word.

But the problem with going after Google is that - unlike typical monopolies - it didn't steal its booty like a pirate in the night. It didn't win by being closed and proprietary. Google won by being open and distributed - which is not the image of the monopolist. The rest of the marketing universe, from media companies to advertising agencies, handed Google its dominance on a silver platter.

Yahoo ran to Google to save it from erstwhile monopolist Microsoft - and to add a few hundred million dollars to Yahoo's bottom line. Google didn't hold up Yahoo; it was the white knight. Together or apart, the two companies account for 80% of US search ads. Note, as a Google executive did for me, that pricing for these ads is not set by Google and Yahoo - which is the danger of monopolies - but by the market in an open auction.

Newspapers in the UK and US hire specialists in search-engine optimisation to make their content more attractive to Google's spiders (v those in France and Belgium that sporadically and suicidally insist that Google stop scraping their headlines).

Last week, Google News announced it would, at its expense, digitise print archives of more than 100 American newspapers, putting their old content online, making it searchable, targeting ads on that content, and giving papers new revenue they desperately need. As we say in New York: what's not to love?

Also last week, NBC announced that it would hand some cable and local advertising inventory to Google to sell. The deal is less about revenue - the inventory at stake is small - than about Google's ability to bring new advertisers to NBC. Google invented ways to serve niche and local advertisers that were too small to be accommodated by big media. Irony noted: old media are too big for the internet; Google is better at serving the small.

Advertising agencies, too, are moulding themselves around Google. When I interviewed Rishad Tobaccowala, head of the advertising lab and thinktank Denou, for my book, What Would Google Do?, he explained that his parent company, Publicis, merged all its digital divisions so it would hold better negotiating leverage with Google, Yahoo, Microsoft, et al. It wanted to be bigger so it - like Google - could consolidate data about audiences and performance and could learn more than any one division could have known before. Google is the model.

Google doesn't always wait for manna to fall on it. It also buys companies to gain dominance. But its acquisition of online giant Doubleclick was approved by the US government only recently. Has Google got too big since then?

I've long argued that we do, indeed, need competition in the ad market. But it's not going to come from regulation or spending years torturing Google as Microsoft was tortured by the US and EU. The way to create competition is

for the media and advertising industries to stop handing their businesses to Google and to get off their butts and create new marketplaces.

I argued in these pages two years ago that we need an open-source ad marketplace to attack Google's opaqueness. Nobody heeded that advice. But in the meantime, the women's network

glam.com has built a formidable advertising empire by curating content sites and selling brand advertising. Glam's CEO, Samir Arora, told me last week that it now serves more than 80 million people worldwide, half in the US. The way to fight Google is to stop feeding it and to start competing with it.

(Disclosure: I own Google stock.)

· Jeff Jarvis is a journalism professor at the City University of New York and blogs at buzzmachine.com